【作者】 努尔模达·达拉拜；

【导师】 吴发启；

【作者基本信息】 西北农林科技大学 ， 水土保持与荒漠化防治， 2007， 硕士

【摘要】 土壤中的硼、铜、锌、铁、锰、钼、氯和钴等微量元素是植物正常生长发育必需的微量元素,它们多是组成酶、维生素和生长激素的成份,直接参与有机体的代谢过程。尽管作物对微量元素的需要量很少,但微量元素在作物的生长发育过程中必不可缺。在土壤中微量元素缺乏或供给不足的时候,则会成为限制产量进一步提高的障碍因素。明确土壤中微量元素的含量、分布、形态和转化的规律,有助于正确判断土壤中微量元素的供给情况。明确风沙区土壤中微量元素的含量及分布特征,探讨不同土地利用方式及农田管理措施下,土壤微量元素含量的变化规律,对正确把握风沙区土壤的微环境状况以及土壤环境对区域大环境的影响,防治沙漠化及沙尘暴,提高农作物产量和当地人民的生活水平中具有重要的指导意义。因此,本文为科学研究项目及其防治沙漠化和沙尘暴的需要,以陕北靖边县北部风沙区土壤为对象,通过野外调查与采样、室内实验与统计分析相结合的方法,研究了黄土高原北部风沙区土壤中植物正常生长发育必需的B、Cu、Zn、Fe和Mn等微量元素的有效态含量及分布特征,分析了影响土壤微量元素含量变化的因素。主要结果如下: (1)土壤中有效态微量元素的含量特征:从全区范围内来看,靖边县北部风沙区土壤中B、Cu、Zn、Fe和Mn等微量元素有效态含量在0-20cm表层(耕层)土壤中的平均值分别为:0.421 mg.kg-1、0.505 mg.kg-1、0.582 mg.kg-1、7.092 mg.kg-1和7.251 mg.kg-1。它们的变幅分别在2.582～0.022 mg.kg-1,1.194～0.158 mg.kg-1,3.944～0.096 mg.kg-1,26.080～2.400 mg.kg-1和13.390～2.082 mg.kg-1之间;同全国土壤微量元素有效态含量分级标准相比较,Cu、Zn、Fe、Mn属于适中水平,B属于缺乏水平。因此,建议该地区今后在种植中应重视硼肥的施用。(2)土壤中有效态微量元素含量的分布特征:在水平方向上,土壤有效态微量元素含量在0-20cm表层(耕层)土壤中的分布特征为:土壤有效态B、Cu、Zn和Mn的含量有由西北向东南增高的趋势,而有效态Fe的分布与B、Cu、Zn和Mn相反,Fe则表现出由东南向西北有所增高的趋势。其原因由土壤质地,成土母质,土壤有机质,土壤酸碱度和风蚀有关。其中红敦界由于界内有无定河流经,地貌类型上属河阶地,其境内含量最高。高家沟在最南部,属山地旱作农田,生产力低下,含量最低。在剖面垂直方向上,靖边县北部风沙区0-20cm表层(耕层)土壤中的有效态微量元素B、Cu、Zn、Fe和Mn的含量明显高于20-40cm和40-60cm土层(底层)的含量。但20-40cm和40-60cm土层的土壤有效态微量元素含量差异不明显。相对来说,20-40cm的土壤有效态微量元素B、Cu和Zn的含量比40-60cm较低,但有效态Fe和Mn在20-40cm的含量比40-60cm较高。这与影响土壤微量元素含量的成土母质、成土条件、土壤有机质、土壤酸碱度及水土流失和土壤风蚀等因素有关。(3)在土壤中有效态微量元素含量变化的影响因子:在黄土高原北部风沙区影响土壤中有效态微量元素含量时空变化的自然因素(内在原因)主要是土壤性质的改变。其当地长期发生的土壤风蚀所引起的土壤有机质含量的降低和pH值的变化有关。而人为因素来说,主要是当地农民为了防治土壤风蚀,保护农田土壤所采取的农田防护林措施和农民为了防风、增产所采取的作物轮作制度、冬季留茬和肥料投入等各种土地利用和农田管理措施有关。因不同的土地利用方式和农田管理措施改变了土壤性质,是影响土壤中有效态微量元素含量变化的外在原因。因此,根据土壤性质,因地制宜地采取合理的土壤管理措施,是农业生产过程中改善土壤微量元素管理的关键。更多还原

【Abstract】 Soil trace elements such as B, Cu, Zn, Mo, Fe, Co are essential elements for plant growth. Trace elements are often components enzymes, vitamins and growth hormones, thus directly participating in the metabolism process of plants. Crop requirements for trace elements are very small, however, they can be not lacking if the crop growth process is to be normal.. If the trace element content of the soil is low or if the trace elements are unavailable to plants, then crop production will be limited. It is important of study the content, distribution, speciation and transformation processes of trace elements in order correctly judge the soil’s ability to supply trace elements to crops. The objective of this study was to investigate the trace element content, speciation, and distribution in a sandy soil. The study also investigated changes in soil trace element content under different land use and farmland management techniques. This study should help scientists to understand the soil micro-environment condition and the influence of the soil environment on the whole environment in the region. The results could help to prevent and control desertification and dust storms, enhance crop yield, and improve the living standard for local people.So, in order to combating wind erosion and sand storm, the paper conducted in sand region of northern jinbian county, combining the methods of investigation and sampling in the wild, and experiment and statistics in the room. We studied on the distribution and content of the trace elements in this region. And analyse the facters affected on its changes. The results are as follows:(1) Soil available trace element contents:The mean content of soil available B, Cu, Zn, Fe and Mn in the entire area in the 0-20cm surface layer (top soil) was: 0.421 mg.kg-1, 0.505 mg.kg-1, 0.582 mg.kg-1, 7.092 mg.kg-1 and 7.251mg.kg-1 respectively. Soil available B, Cu, Zn, Fe, and Mn ranged from 2.582 ~ 0.022 mg.kg-1, 1.194 ~0.158 mg.kg-1, 3.944 ~ 0.096 mg.kg-1, 26.080 ~ 2.400 mg.kg-1and 13.390 ~ 2.082 mg.kg-1. According to national standard classes, the content of Cu, Zn, Fe and Mn are suitable, but B is lower. So, it is import to think much of using fertilizer B in the future.(2) Distribution of soil available trace elements:The distribution soil available trace elements content in the 0-20cm surface layer of this region can be summarized in the following way. Soil available B, Cu, Zn and Mn increased from northwest to southeast, but soil available Fe increased from southeast to northwest. The reasons for the differences in the distribution of trace elements can be related to soil texture, soil parent material, soil pH and the soil wind erosion. In addition, soil trace element contents were generally highest at Hongdunjie, which is along the Wuding River and lowest at Gaojiagou, which is dry farm land.In terms of vertical distribution, available B, Cu, Zn, Fe and Mn contents was significantly higher in the 0-20cm layer surface soil compared to the 20-40cm and 40-60cm depths. Differences in the trace element content of the 20-40cm and 40-60cm layers were not significant. In contrast, the available B, Cu and Zn in the 20-40cm layer was lower than in the 40-60cm soil layer, but available Fe and Mn in 20-40cm soil layer was higher than in the 40-60cm..(3) Reasons for the observed changes in available soil trace element contents:The natural factors (intrinsic reason) which affect the soil trace element content include: soil properties, especially soil organic matter and soil pH, and long-term wind erosion. Human factors mainly include the establishment of a shelter forest, as well as other land utilization and farmland management measures which local farmers use to prevent and control wind erosion. These factors include protection measures to enhance production, prevent wind, such as crop rotation systems, keeping stubble over the winter, and fertilization. All of these affect soil characteristics and lead to changes in the effectiveness of soil trace elements. Therefore, the adjustment of farming according to soil characteristics and local conditions is the key to soil trace element management.更多还原